Rotary lawn mowers, meaning those with a cutter rotating at high speed about a vertical axis within a housing, are presently very popular. They sometimes propel loose objects rearwardly against the legs of the user, however, and they are capable of injuring his toes if he allows his foot to enter the path of the whirling blade.
It has accordingly been the custom to provide some sort of rear shield of the back of such mowers to protect the user against these happenings. Shields of many degrees of complexity have been proposed, but it has been uniformly found that the shields so interfere with convenient use of the mowers, particularly in backward cuts, that the users remove them, preferring to work "carefully" with an unshielded machine rather than to work safely with a mower of reduced maneuverability.